| 摘要 |
PURPOSE:To satisfy the noise margin standard, by lowering the level of an undesired wave in case the undesired wave has been mixed into the band in which a piolt signal is used. CONSTITUTION:The output of a signal common amplifier 1b is applied to the signal detecting parts 2'-1-2'-n as well as to a rectifier 1c. With an input of an undesired wave, the DC output level of the rectifier 1c increases to generate an output from a level comparator 1d. The output of the comparator 1d is supplied to a variable gain amplifier 2-1b' to lower the gain of this amplifier. In such a way, the level of an undesired wave emerging at the output of a narrow band pass filter 2-1a is reduced. |
